The validity of God’s command

I’ll present everything for convenience. I think it can also be understood from reading the last question alone.

My original question:
In the fourth notebook, you provide proof that there is a dependence between the claims “moral judgment has meaning” and “God exists.”
It seems that only two possibilities have been raised that allow for the existence of morality: subjective morality and (let’s call it) “divine” morality. I think there is a third possibility that would also allow for meaning in moral judgment.
It is possible that there is a fixed system of laws, perhaps we could even call it primordial, and according to which morality is determined and according to which we can judge what is a moral act. I don’t think we need to say that God created this system of laws…
Or did you mean that it has no binding force towards us if it was created by God?

The answer:
Indeed. The fact that there are laws does not mean that I will obey them or that I must obey them. This is the naturalistic fallacy. Beyond that, even if such laws exist, there is room for the question of who or what created them? And even if they are ancient, I explained that there is the principle of sufficient reason.

question:
I didn’t understand why if the system of moral laws was created by God, then it is binding on us? (By the way, was it created by God, according to the Rabbi?)
(Why can’t the existence of that theoretical system of laws be justified in the same way that the existence of its creator – God – can be justified?)

answer:
The legal system is not an entity but rules. The rules are binding by virtue of someone who established them. Without such someone, the rules have no validity.
My fundamental argument is that in the absence of God, moral laws have no validity. I personally also believe that if God did create the system, it has validity. There are of course those who argue about that. But anyone who argues about the fundamental argument is simply mistaken.

question:
Why does God have more binding force than the rules (- the moral law system) themselves? In other words – what binding force does God have that the law system cannot have?